1. Field of the Invention
The present invention relates to hot melt type traffic paint compositions and, more particularly, to hot melt type traffic paint compositions containing as a binder a partially ring-hydrogenated aromatic hydrocarbon resin prepared from cracked oil fractions obtainable by cracking of petroleum.
2. Description of the Prior Art
Generally, hot melt type traffic paints contain thermoplastic resins (binders), plasticizers, pigments, fillers, glass beads or the like. These traffic paints are coated on road surfaces by melting them at 150.degree. to 250.degree. C. and become fixed thereon upon cooling. They are employed for white or yellow markings on road surfaces.
Conventional thermoplastic resins of hot melt type traffic paints may include maleic acid resins modified by rosin, alkyd resins, hydrocarbon resins and the like. The rosin-modified maleic acid resins are extensively employed. The use of rosin as a raw material, however, may give rise to some disadvantages with respect to stabilized supply and cost because rosin is a naturally occurring material. Furthermore, traffic paints for which rosin-modified maleic acid resins are employed have other disadvantages in that their whiteness is insufficient and cracks tend to be produced.
In order to overcome such difficulties associated with rosin, hydrocarbons resins from petroleum have been used instead; they are stable in supply and are cheaper than rosin, said hydrocarbon resins being prepared from cracked oil fractions by cracking of petroleum.
When aliphatic unsaturated hydrocarbon resins prepared from cracked oil fractions containing aliphatic unsaturated hydrocarbons having boiling points in the range of 20.degree. to 100.degree. C. are used for hot melt type traffic paints, such paints still have disadvantages in that their flowability is insufficient, fillers used in them tend to sediment faster and cracks are still produced.
On the other hand, aromatic hydrocarbon resins prepared from cracked oil fractions containing unsaturated aromatic hydrocarbons having boiling points within the range of 140.degree. to 280.degree. C. are not satisfactory with respect to heat resistance and anti-weathering, so that they are also unacceptable as binders for traffic paints of hot melt type.
It has previously been found, however, that resins derived from fractions obtained by distillation of fractions having boiling points in the range of 140.degree. to 220.degree. C. from cracked oil fractions prepared by cracking of petroleum and by complete separation of specific ingredients, are favorable in heat resistance, and traffic paints using such resins are satisfactory in sedimentation of fillers and in dirt-repellency. This feature has already been disclosed in the Japanese Patent Publication No. 34,078/1975. It has been found, moreover, that this type of traffic paint can provide a sufficient resistance to yellowing to allow the use of a white pigment such as titanium oxide, if it is used in a relatively large amount; however, when white pigments such as titanium oxide are used in small amounts or when they are applied under severe conditions, they tend to provide coatings which are prone to turn yellow.
As a result of extensive studies aimed at solving these disadvantages, it has now been found that the problems stated above can be solved by using aromatic hydrocarbon resins which are prepared by partially hydrogenating the aromatic rings of aromatic hydrocarbon resins derived from the aforementioned fractions by separating out specific ingredients; thus, the present invention has been proposed.
Accordingly, the primary object of the present invention is to provide hot melt type traffic paint compositions having improved anti-weathering characteristics, a favorable heat resistance, and improved flow characteristics.
Another object of the present invention is to provide hot melt type traffic paint compositions containing as binders partially ring-hydrogenated resins obtainable by hydrogenating 20 to 70% of the aromatic rings of an aromatic hydrocarbon resin obtained by polymerization, in the presence of a Friedel-Crafts catalyst, of fractions prepared so as to have a conjugated diolefin content in an amount of not more than 1.0 wt % and in a ratio of not more than 3.0% of the total amount of polymerizable ingredients, and a total content of indene and its alkyl derivatives in an amount of not more than 4.0 wt % and in a ratio of not more than 12.0% of the total amount of polymerizable ingredients, said fractions having boiling points in the range of 140.degree. to 220.degree. C. and obtained by distillation of cracked oil fractions prepared by cracking of petroleum.